This is a longitudinal study of the daily urinary output and the concentrations in whole blood of cobalt and chromium in patients with metal-on-metal resurfacings over a period of four years. Twelve-hour urine collections and whole blood specimens were collected before and periodically after a Birmingham hip resurfacing in 26 patients. All ion analyses were carried out using a high-resolution inductively-coupled plasma mass spectrometer. Clinical and radiological assessment, hip function scoring and activity level assessment revealed excellent hip function. There was a significant early increase in urinary metal output, reaching a peak at six months for cobalt and one year for chromium post-operatively. There was thereafter a steady decrease in the median urinary output of cobalt over the following three years, although the differences are not statistically significant. The mean whole blood levels of cobalt and chromium also showed a significant increase between the pre-operative and one-year post-operative periods. The blood levels then decreased to a lower level at four years, compared with the one-year levels. This late reduction was statistically significant for chromium but not for cobalt. The effects of systemic metal ion exposure in patients with metal-on-metal resurfacing arthroplasties continue to be a matter of concern. The levels in this study provide a baseline against which the
The long-term effects of metal-on-metal arthroplasty are currently under scrutiny because of the potential biological effects of metal wear debris. This review summarises data describing the release, dissemination, uptake, biological activity, and potential toxicity of metal wear debris released from alloys currently used in modern orthopaedics. The introduction of risk assessment for the evaluation of metal alloys and their use in arthroplasty patients is discussed and this should include potential harmful effects on immunity, reproduction, the kidney, developmental toxicity, the nervous system and carcinogenesis.
We evaluated the concentrations of chromium and cobalt ions in blood after metal-on-metal surface replacement arthroplasty using a wrought-forged, high carbon content chromium-cobalt alloy implant in 64 patients. At one year, mean whole blood ion levels were 1.61 μg/L (0.4 to 5.5) for chromium and 0.67 μg/L (0.23 to 2.09) for cobalt. The pre-operative ion levels, component size, female gender and the inclination of the acetabular component were inversely proportional to the values of chromium and/or cobalt ions at one year postoperatively. Other factors, such as age and level of activity, did not correlate with the levels of metal ions. We found that the levels of the ions in the serum were 1.39 and 1.37 times higher for chromium and cobalt respectively than those in the whole blood. The levels of metal ions obtained may be specific to the hip resurfacing implant and reflect its manufacturing process.
The menisci of the knee have an important role in load-bearing and shock absorption within the joint. They may also function as secondary stabilisers, have a proprioceptive role, and aid the lubrication and nutrition of the articular cartilage. Complete or partial loss of a meniscus can have damaging effects on a knee, leading to serious long-term sequelae. This paper reviews the consequences of meniscectomy and summarises the body of evidence in the literature regarding those factors most relevant to long-term outcome.
New developments in osteotomy techniques and methods of fixation have caused a revival of interest of osteotomies around the knee. The current consensus on the indications, patient selection and the factors influencing the outcome after high tibial osteotomy is presented. This paper highlights recent research aimed at joint pressure redistribution, fixation stability and bone healing that has led to improved surgical techniques and a decrease of post-operative time to full weight-bearing.
We have used the Oxford hip score to monitor the progress of 1908 primary and 279 revision hip replacements undertaken since the start of 1995. Our review programme began in early 1999 and has generated 3900 assessments. The mean pre-operative scores for primary and revision cases were 40.95 and 40.11, respectively. The mean annual score for primary replacement at between 12 and 84 months ranged between 20.60 and 22.57. A comparison of cross-sectional and longitudinal data showed no significant differences. All post-operative reviews showed a significant improvement (p ≤ 0.0001). The 50- to 60-year-old group scored significantly better than the patients over 80 years of age up to 48 months (p <
0.01). A subgroup of 826 National Health Service (NHS) and 397 private patients, treated by the senior author (2292 Oxford assessments), had a higher (i.e. worse) mean pre-operative score for the NHS patients (p ≤ 0.001). The private patients scored better than the NHS group up to 84 months (p <
0.05). Patients treated by a surgeon performing more than 100 replacements each year had a significantly better outcome up to five years than those operated on by surgeons performing fewer than 20 replacements each year. The age of the patients at the time of operation, and their pre-operative level of disability, have both been identified as affecting the long-term outcome. Awareness of the influence of these factors should assist surgeons to provide balanced advice.
Posterolateral rotatory instability is the most common type of symptomatic chronic instability of the elbow. In this condition the forearm complex rotates externally in relation to the humerus, causing posterior subluxation or dislocation of the radial head. The lateral ligament complex, radial head and coronoid process are important constraints to posterolateral rotatory instability, and their disruption is involved in the pathogenesis of this condition. The diagnosis relies on a high index of clinical suspicion, active and passive apprehension tests, and examination under anaesthesia. Surgical treatment has given consistently successful results. Open reconstruction of the lateral ligaments with a tendon graft has been the procedure of choice, with arthroscopic techniques emerging as a potential alternative.
We carried out a prospective study of 118 hydroxyapatite-coated, cementless total knee replacements in patients who were ≤ 55 years of age and who had primary (92; 78%) or post-traumatic (26; 22%) osteoarthritis. The mean period of follow-up was 7.9 years (5 to 12.5). The Knee Society clinical scores improved from a pre-operative mean of 98 (0 to 137) to a mean of 185 (135 to 200) at five years, and 173 (137 to 200) at ten years. There were two revisions of the tibial component because of aseptic loosening, and one case of polyethylene wear requiring further surgery. There was no osteolysis or progressive radiological loosening of any other component. At 12 years, the overall rate of implant survival was 97.5% (excluding exchange of spacer) and 92.1% (including exchange of spacer). Cementless total knee replacement can achieve excellent long-term results in young, active patients with osteoarthritis. In contrast to total hip replacement, polyethylene wear, osteolysis and loosening of the prosthesis were not major problems for these patients, although it is possible that this observation could change with longer periods of follow-up.
We reviewed 78 femoral and tibial nonunions treated between January 1992 and December 2003. Of these, we classified 41 in 40 patients as complex cases because of infection (22), bone loss (6) or failed previous surgery (13). The complex cases were all treated with Ilizarov frames. At a mean time of 14.1 months (4 to 38), 39 had healed successfully. Using the Association for the Study and Application of the Methods of Ilizarov scoring system we obtained 17 excellent, 14 good, four fair and six poor bone results. The functional results were excellent in 14 patients, good in 14, fair in two and poor in two. A total of six patients were lost to follow-up and two had amputations so were not evaluated for final functional assessment. All but two patients were very satisfied with the results. The average cost of treatment to the treating hospital was approximately £30 000 per patient. We suggest that early referral to a tertiary centre could reduce the morbidity and prolonged time off work for these patients. The results justify the expense, but the National Health Service needs to make financial provision for the reconstruction of this type of complex nonunion.
The recent resurgence in the use of metal-on-metal bearings has led to fresh concerns over metal wear and elevated systemic levels of metal ions. In order to establish if bearing diameter influences the release of metal ions, we compared the whole blood levels of cobalt and chromium (at one year) and the urinary cobalt and chromium output (at one to three and four to six years) following either a 50 mm or 54 mm Birmingham hip resurfacing or a 28 mm Metasul total hip replacement. The whole blood concentrations and daily output of cobalt and chromium in these time periods for both bearings were in the same range and without significant difference.
We studied retrospectively the results of revision arthroplasty of the elbow using a linked Coonrad-Morrey implant in 23 patients (24 elbows) after a mean follow-up period of 55 months. According to the Mayo Elbow Performance Score, 19 elbows were satisfactory, nine were excellent and ten good. The median total score had improved from 35 points (20 to 75) before the primary arthroplasty to 85 points (40 to 100) at the latest follow-up. There was a marked relief of pain, but the range of movement showed no overall improvement. Two patients had a second revision because of infection and two for aseptic loosening. The estimated five-year survival rate of the prosthesis was 83.1% (95% confidence interval 61.1 to 93.3). Revision elbow arthroplasty using the Coonrad-Morrey implant provided satisfactory results but with complications occurring in 13 cases.